1. Field of the Invention
The field of the invention is the field of automatically processing mailpieces, it being possible for said mailpieces to be letters, “flats” (i.e. large-format flat articles, e.g. magazines or newspapers wrapped in plastic or in paper), or indeed parcels.
More particularly, the invention relates to a method of processing mailpieces for sorting mailpieces into sequence in a postal sorting machine depending on delivery points of delivery rounds, in which method the mailpieces are grouped together into various batches associated with one or more delivery rounds and are sorted in the postal sorting machine by batch as a function of various sorting plans associated respectively with the various batches of mailpieces, each sorting plan associated with a batch of mailpieces defining an ordered list of delivery points of one or more delivery rounds, with delivery points being put into correspondence with sorting outlets of the postal sorting machine.
2. Description of the Related Art
Patent Document EP 2 091 012 discloses a method of processing mailpieces for sorting mailpieces into sequence in a postal sorting machine depending on delivery points of delivery rounds, in which method the mailpieces are grouped together into various batches associated with one or more delivery rounds and are sorted in the machine by batch as a function of various sorting plans associated respectively with the various batches of mailpieces, each sorting plan associated with a batch of mailpieces defining an ordered list of delivery points of one or more delivery rounds. Once the quantity of mailpieces in each group is known, articles that have similar identifiers are allocated the same sorting outlet.
Patent Document EP 1 872 869 discloses a method that consists in obtaining information about the volume of the postal articles to be sorted into a plurality of groups of mail. Each group of mail comprises a plurality of postal articles, each of which has a delivery identifier. A sorting bin is allocated for each group of mail. The identifier on each postal article is detected and the postal article is then conveyed in response to said detection to an allocated mail sorting bin corresponding to the delivery identifier.
Patent Document U.S. Pat. No. 6,703,574 discloses a method of sorting mailpieces into sequence depending on delivery points of delivery rounds. In that method, simulations are performed before machine-sorting the mailpieces so as to assess the occupancy of the sorting outlets of the machine and so as to reorganize the corresponding sorting plan in order to prevent the sorting outlets from overflowing.
Currently, sorting machines are controlled using pre-established sorting plans that are configured by taking into account the number of sorting outlets of the machine, the number of delivery points for each delivery round to be sequenced, the number of sorting passes to be performed for sequencing the mailpieces for delivery by a person, and where applicable the storage capacity of the sorting outlets of the machine. For example, some sorting machines in inward sorting centers have twenty sorting outlets (one of which is reserved for rejects), and so they have a sorting capacity of about six thousand eight hundred delivery points, which is equivalent to five delivery rounds each including, on average, one thousand three hundred delivery points.
Sorting plans that are static do not take into account the dynamic characteristics of the flows of mail to be sorted. Such sorting plans are configured to be balanced, i.e. to use all of the sorting resources of the machine if it is considered that the flows of mail to be sorted are always distributed uniformly over the delivery points of the delivery rounds.
However, on arriving at an inward sorting center (arrival sorting center) where the mailpieces are sorted for delivery by the delivery person, the flow of mail is never of constant volume and is never distributed uniformly over the delivery points, which can, as indicated above, give rise to sorting outlets overflowing, and also to non-optimum use of the sorting machine. Thus, for some batches of mailpieces to be sorted on any one day, certain sorting outlets of the machine can remain empty due to absence of mail for certain series of delivery points. That situation ultimately leads to lowering of the throughput rate of the machine due to a low volume of mail to be sorted, thereby increasing the mail processing costs accordingly.